Methods of training to detect powdered explosive-detection training aids

ABSTRACT

The present application is directed to a packaging for a powdered explosive-detection training aid which may include first and second opposing flexible sheets heat sealed together along less than a periphery thereof and defining a storage compartment therebetween, wherein an unsealed portion of the periphery defines an opening to the storage compartment, wherein at least a portion of the first opposing flexible sheet is a semipermeable material permeable to a vapor emitted from the powdered explosive-detection training aid, with the second opposing flexible sheet being impermeable to the powdered explosive-detection training aid vapor; and a sealing member, wherein the sealing member is secured to the first opposing flexible sheet and, in a closing position, covers the semipermeable portion of the first opposing flexible sheet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Nonprovisional application Ser.No. 16/279,121 entitled “Packaging for Powdered Explosive-DetectionTraining Aids and Uses Thereof,” filed on Feb. 19, 2019; the disclosureof which is incorporated herein by reference in its entirety.

STATEMENT OF GOVERNMENT INTEREST

The present invention was made by one or more employees of the UnitedStates Department of Homeland Security in the performance of officialduties.

BACKGROUND

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description, which may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

Scent-detecting animals, such as canines, are routinely trained todetect explosives using samples of genuine explosives orpseudo-explosive training aids. Such substances are typically placedinto a packaging, and then a canine, for example, is conditioned torespond to the vapor plumes emanating from the packaging. However, ascent-detecting animal may readily be exposed to unintentional explosiveodors due to cross-contamination of the training area, thus skewingresults and confusing both animals and handlers. Avoiding contaminationof areas used to train animals to detect explosives andpseudo-explosives is consequently desirable.

SUMMARY

The present inventor recognized that the packaging commonly used tocontain explosives and pseudo-explosives during explosive-detectiontraining of an animal is often so porous that explosive particulatematter and dust filter through the packaging and contaminate areas usedfor training. Hence, the present inventor developed a packaging that iscapable of containing explosive particulate matter, but is permeable toexplosive vapors. Moreover, the present packaging is resistant to liquidwater, thus allowing the packaging to be readily used with hydrophilicexplosives. Further, the puncture-resistant properties of the presentpackaging allow it to be conveniently used to train, e.g. canines, todetect explosives. Accordingly, the packaging of the present disclosurecan be used to contain a wide variety of powdered explosive-detectiontraining aids and allow, e.g., a canine, to detect the vapors fromexplosive materials without contaminating training areas with explosiveparticulates.

In one aspect, the present application is directed to a packaging for apowdered explosive-detection training aid including: first and secondopposing flexible sheets, wherein the first and second opposing flexiblesheets are heat sealed together along less than a periphery thereof anddefine a storage compartment therebetween, wherein an unsealed portionof the periphery defines an opening to the storage compartment, whereina melting point of the first opposing flexible sheet is substantiallythe same as a melting point of the second opposing flexible sheet,wherein at least a portion of the first opposing flexible sheet is asemipermeable material, wherein the semipermeable material is permeableto a vapor emitted from the powdered explosive-detection training aid,and wherein the semipermeable material is impermeable to liquid waterand particulate matter from the powdered explosive-detection trainingaid, wherein the second opposing flexible sheet is impermeable to thepowdered explosive-detection training aid vapor; and a sealing member,wherein the sealing member is secured to the first opposing flexiblesheet and, in a closing position, covers the semipermeable portion ofthe first opposing flexible sheet.

In another aspect, the present disclosure is directed to a packagedpowdered explosive-detection training aid including: first and secondopposing flexible sheets with a powdered explosive-detection trainingaid therebetween, the opposing flexible sheets being heat sealed along aperiphery thereof, wherein a melting point of the first opposingflexible sheet is substantially the same as a melting point of thesecond opposing flexible sheet, wherein at least a portion of the firstopposing flexible sheet is a semipermeable material, wherein thesemipermeable material is permeable to a vapor emitted from the powderedexplosive-detection training aid, wherein the semipermeable material isimpermeable to liquid water and particulate matter from the powderedexplosive-detection training aid, wherein the second opposing flexiblesheet is impermeable to the powdered explosive-detection training aidvapor, and a sealing member, wherein the sealing member is secured tothe first opposing flexible sheet and, in a closing position, covers thesemipermeable portion of the first opposing flexible sheet.

The present disclosure is also directed to a method of training a mammalto detect a powdered explosive-detection training aid, which methodincludes: placing a packaged powdered explosive-detection training aidin a training area, wherein the packaged training aid comprises: firstand second opposing flexible sheets with the powderedexplosive-detection training aid therebetween, the opposing flexiblesheets being heat sealed along a periphery thereof, wherein a meltingpoint of the first opposing flexible sheet is substantially the same asa melting point of the second opposing flexible sheet, wherein at leasta portion of the first opposing flexible sheet is a semipermeablematerial, wherein the semipermeable material is permeable to a vaporemitted from the powdered explosive-detection training aid, wherein thesemipermeable material is impermeable to liquid water and particulatematter from the powdered explosive-detection training aid, wherein thesecond opposing flexible sheet is impermeable to the powderedexplosive-detection training aid vapor; conditioning the mammal todetect the vapors permeating from the packaged powderedexplosive-detection training aid, thereby training the mammal to detectthe powdered explosive-detection training aid.

Further areas of applicability of the packaging of the presentdisclosure will become apparent from the detailed description andexamples provided hereinafter. It should be understood that the detaileddescription and specific examples, while providing specific embodimentsof the disclosure, are intended for illustration only and should in noway limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

An appreciation of the disclosure and many of the attendant advantagesthereof may be understood by reference to the accompanying drawings.Included in the drawings are the following figures.

FIG. 1 depicts an embodiment of the packaging of the present disclosureas described in the detailed description.

FIGS. 2A-2D depict different shapes of the present packaging, i.e., arectangle (FIG. 2A), a triangle (FIG. 2B), a hexagon (FIG. 2C) and apistol-type formation (FIG. 2D).

FIG. 3 depicts an embodiment of the packaging of the present disclosure,which includes a sealing member in an open position, as described in thedetailed description.

FIG. 4 depicts an embodiment of the packaging of the present disclosure,which includes a sealing member in a closed position, as described inthe detailed description.

FIG. 5A depicts a schematic showing the selective permeability of thepresent packaging as described in the detailed description.

FIG. 5B depicts a schematic showing the selective permeability of thepresent packaging as described in the detailed description.

FIG. 5C depicts a schematic showing the selective permeability of thepresent packaging as described in the detailed description.

FIG. 6 depicts a calibration curve for trinitrotoluene as described inthe Examples.

FIG. 7 depicts a calibration curve for dinitrotoluene as described inthe Examples.

FIG. 8 depicts a chromatogram showing that triacetone triperoxidepermeated from a packaging of the present disclosure as evidenced from aheadspace glass vessel sample as described in the Examples.

FIG. 9 depicts a chromatogram showing the presence of triacetonetriperoxide in a headspace glass vessel as described in the Examples.

DETAILED DESCRIPTION

The present disclosure is directed to a packaging for a powderedexplosive-detection training aid as described herein. Referring now tothe drawings, FIG. 1 depicts a packaging 100 for a powderedexplosive-detection training aid according to the present disclosure.The packaging includes first 104 and second 106 opposing flexiblesheets. In some embodiments, the first 104 and second 106 opposingflexible sheets are heat sealed together along less than a peripherythereof 102. An unsealed portion of the periphery defines an opening 108to a storage compartment.

In some embodiments, at least a portion of the first opposing flexiblesheet 104 is a semipermeable material as described herein. For example,the entire first opposing flexible sheet 104 may be a semipermeablematerial. In other embodiments, at least 10%, such as at least 25%, suchas at least 50% or such as at least 75% of the first opposing flexiblesheet 104 is made from the semipermeable material.

As used herein the terms “semipermeable” or “selectively permeable”refer to a material that is permeable to a vapor emitted from a powderedexplosive-detection training aid, but impermeable to particulate matterfrom the powdered explosive-detection training aid. In some embodiments,the semipermeable material is impermeable to liquid water, but permeableto water vapor. In some embodiments, the semipermeable material isimpermeable to bacteria.

In some embodiments, the semipermeable material is spun-bondedpolyolefin. The spun-bonded polyolefin may be prepared from high densitypolyethylene. Typically, the semipermeable material contains pores lessthan 1 micron in diameter, such as about 0.3 microns or less indiameter, such as about 0.22 microns in diameter. Semipermeable materialsuitable for use with the packaging of the present disclosure includes,for example, the commercially available TYVEK® (E. I. du Pont de Nemoursand Company (“DuPont”), Wilmington, Del.), such as TYVEK® 1059B orTYVEK® 1073B.

In some embodiments, the second opposing flexible sheet 106 is a polymerfilm, such as a high density (e.g., 930 to 970 kilograms/meter³)polyethylene (HDPE) film. In some embodiments, HDPE is prepared from ahigh molecular weight resin, such as a commercially available HD960 fromHuntsman Packaging Corp. (South Deerfield, Mass.) or ALATHON® L5005 fromFina Oil and Chemical Co. (Deer Park, Tex.).

Examples of high molecular weight, high density polyethylene include thecommercially available PRECISION CLEAN™ HD (Fisher Container HoldingsLLP, Buffalo Grove, Ill.). This HDPE film comes in a variety of gauges,but typically a thickness of about 3 millimeters is used with thepresent packaging. In some embodiments the material of the secondopposing flexible sheet is impermeable to vapor particles includingthose from powdered explosive-detection training aids and water. In someembodiments, the material of the second opposing flexible sheet isimpermeable to water in a liquid phase.

In some embodiments, the first opposing flexible sheet 104 hassubstantially the same melting point as the second opposing flexiblesheet 106. As used herein “substantially the same melting point” refersto a difference in melting points between, for example, the first 104and second 106 opposing flexible sheets, which is no more than about 15°C., such as no more than about 10° C., such as no more than about 8° C.,such as no more than about 6° C., such as no more than about 2° C. orsuch as no more than about 1° C.

In some embodiments, the first 104 and second 106 opposing flexiblesheets are heat sealed together around less than an entirety of theperiphery thereof. In the heat sealing process, the two opposingflexible sheets 104 and 106, for example, are heat sealed around lessthan the periphery using, e.g., a heat-sealing machine, such as astandard commercially available “twin seal” machine from Amplas, Inc.(Green Bay, Wis.). In some embodiments, heat and pressure are applied toeach of the opposing flexible sheets, e.g., 20-40 psi. In someembodiments, the opening 108 may also be heat sealed to close thepackaging after placing a powdered explosive-detection training aid intothe packaging. Accordingly, in some embodiments the first and secondopposing flexible sheets 104 and 106 are heat sealed around the entiretyof the periphery thereof.

FIGS. 2A-2D depict various embodiments of the present packaging. Asindicated in FIGS. 2A-2D, the present packaging may be of a variety ofdimensions and varying seal widths. For example, FIGS. 2A-2D depictpackaging in the form of a rectangle FIG. 2A, a triangle FIG. 2B, ahexagon FIG. 2C, or a pistol form FIG. 2D. In these embodiments, anopening, such as the opening 108 depicted is FIG. 1 is heat sealedafter, e.g., placing a powdered explosive-detection training aid intothe packaging. Accordingly, in these embodiments the seal 202 surroundsthe entire periphery of the packaging.

In some embodiments, the bags are between 3 and 60 inches wide and 3 and60 inches long, depending on need. The seals can vary in width between ⅛inch and ¾ inch. Commonly, the present packages have a seal width of ⅛inch.

FIG. 3 depicts an embodiment of a packaging 300, wherein only a portion306 of the first opposing flexible sheet 322 is a semipermeablematerial. In some embodiments, the portion of the first opposingflexible sheet 322, which is not a semipermeable material, may be madeof the same material as the second opposing flexible sheet (not shown),e.g., HDPE as described herein. FIG. 3 further shows a heat seal 308around the periphery of the first 322 and second (not shown) opposingflexible sheets, a sealing member 302 comprising a tab 324 and anattachment member 304.

The sealing member 302, depicted here in the open position, may besecured to the first opposing flexible sheet 322 via the attachmentmember 304. Sealing member 302 may cover the entirety of thesemipermeable portion 306 of the first opposing flexible sheet 322. Insome embodiments, the tab 324 may be used to readily close sealingmember 302. Typically, the sealing member 302 and optionally the tab 324is/are in sealing contact with a vapor impermeable portion of the firstopposing flexible sheet 322.

In some embodiments, the sealing member 302, tab 324 and/or theattachment member 304 comprise a butyl rubber. Butyl rubber is asynthetic rubber, a copolymer of isobutylene with isoprene. Butyl rubberis produced by polymerization of about 98% of isobutylene with about 2%isoprene. Typically, butyl rubber is gas and moisture impermeable andresistant to heat, aging and weather.

In some embodiments, the sealing member 302, tab 324 and/or theattachment member 304 is/are attached to a first opposing flexible sheet322 with a pressure sensitive-adhesive. As used herein“pressure-sensitive adhesives” refer to a category of adhesive that, indry form, are permanently tacky at room temperature. Pressure-sensitiveadhesives can adhere to a variety of substrates when applied withpressure; do not require activation by water, heat, or solvents; andgenerally have sufficient cohesive strength to be handled with thefingers. Examples of suitable pressure-sensitive adhesives for use withthe present packaging include rubber based adhesives, acrylic adhesiveand silicone adhesives.

In some embodiments, rubber-based pressure sensitive adhesives are usedto attach the sealing member 302, tab 324 and/or attachment member 304to the first opposing flexible sheet 322. In some embodiments,rubber-based pressure sensitive adhesives are synthetic, nonlatexrubbers (styrene block copolymers) formulated with tackifying resins,oils, and antioxidants. These pressure-sensitive adhesives provide goodto excellent initial tack and adhesion along with excellent adhesion tomaterials such as that of the first opposing flexible sheet 322. In someembodiments, rubber based adhesives do not demonstrate good temperatureresistance (typically <150° F.) or resistance to environmental stressessuch as sterilization ultraviolet rays.

In some embodiments, the present packaging is not autoclavable orsterilizable. In other embodiments, the present packaging isautoclavable or sterilizable.

FIG. 4 depicts an implementation 400 of the present packaging showing asealing member 428 that is secured to a portion of a first 422 opposingflexible sheet in a closing position. The sealing member includes a tab420. Typically, the sealing member 428 has dimensions greater than thatof the semipermeable portion (not shown) of the first opposing flexiblesheet 422 and is in sealing contact with the vapor impermeable portionof the first opposing flexible sheet 422.

FIGS. 5A-5C depict a packaging embodiment 500 showing how vaporparticles from a powdered explosive-detection training aid pass througha semipermeable material of the present packaging material. FIG. 5A is aschematic of a first opposing flexible sheet 514, a second opposingflexible sheet 516, a storage compartment 510 and a semipermeableportion 506 of a first opposing flexible sheet 514. An implementation ofa powdered explosive-detection training aid comprising explosiveparticulates 504 and explosive vapor particles 502 is also depicted.

FIG. 5B depicts a heat sealed storage compartment 510 containingparticulate explosives 504 and explosive vapor particles 502. Althoughthe storage compartment 510 is sealed, the semipermeable portion 506 ofthe first opposing flexible sheet 514 allows the explosive vaporparticles to exit the packaging 500. The particulate explosives 504 aretoo large to exit the pores of the semipermeable material 506.

FIG. 5C depicts an implementation 500 of the present packaging with asealing member 556 in the closed position. In these embodiments, neitherthe particulate explosives 504 nor the explosive vapor particles 502 areable to exit the pores of the semipermeable material 506 of the firstopposing flexible sheet 514.

In another aspect, the present disclosure is directed to a packagedpowdered explosive-detection training aid comprising the packagingaccording to the present disclosure, wherein the packaging contains apowdered explosive-detection training aid in the storage compartment.

As used herein, the term “powdered explosive-detection training aid”encompasses genuine explosives in powdered form and non-hazardousexplosives that may be used for security training, also known aspseudo-explosives. Examples of pseudo-explosives include impuritiesand/or degradation products of genuine explosives. Typical examples ofpseudo-explosives include 2,4-dinitrotoluene, 2,6-dinitrotoluene,terpenes, cyclohexanone, 2-ethyl-1-hexanol, diphenylamine,dimethyldinitrobutane and ethyl centralite and combinations thereof.

In some embodiments, the powdered explosive-detection training aid isselected from ammonium nitrate, double based smokeless powder,hexamethylene triperoxide diamine, single based smokeless powder,RDX-based plastic explosives (e.g., Composition C-4), triacetonetriperoxide, and combinations thereof. In other embodiments, thepowdered explosive-detection training aid is a hydrophilic powderedexplosive-detection training aid. Typical examples of hydrophilicpowdered explosive-detection training aids include ammonium nitrateprills, ammonium nitrate/fuel oil, urea nitrate, potassium chlorate,potassium perchlorate, tetryl, trinitrotoluene, and combinationsthereof. The packaged powdered explosive-detection training aid of thepresent disclosure may include any of the powdered explosive-detectiontraining aids described herein, such as the hydrophilic powderedexplosive-detection training aids.

In some embodiments, the packaging of the present disclosure containinga powdered explosive-detection training aid is heat sealed around theperiphery. The present packaged powdered explosive-detection trainingaid, further, typically contains a sealing member as described herein,which is in a closed position. In some embodiments, the sealing membercovers the semipermeable portion of the first opposing flexible sheet asherein described, which prevents vapor plumes, including vapor plumesfrom the powdered explosive-detection training aid, from escaping theinstant packaging. The packaged powdered explosive-detection trainingaid may be stored until use, such as for a day, a week, three or moremonths or up to one year.

Methods

In another aspect, the present disclosure is directed to a method oftraining an animal to detect a powdered explosive-detection trainingaid. In some embodiments, the animal is a mammal. Typically, the mammalis a domestic dog. However, in some embodiments, the mammal is a rodent,such as a rat or a mouse.

In some embodiments, a human trainer inserts samples of a powderedexplosive-detection training aid as described herein into an opening ofa storage compartment of the present packaging. The amount of powderedexplosive-detection training aid inserted into the present packaging maybe in any amount, such as from 1 gram to 900 grams, such as about 115grams or 50 grams.

Typically, after placing the powdered explosive-detection training aidinto the present packaging, the opening of the package as describedherein is closed by heat sealing, as also herein described. In someembodiments, a sealing member is placed into the closed position asdescribed herein, thus preventing the vapor particles from the powderedexplosive-detection training aid from permeating through the packaging.

In some embodiments, the packaged powdered explosive-detection trainingaid is placed into a training area, e.g., within an airplane. In someembodiments, the sealing member is placed into the open position orremoved, thus allowing the vapor particles from the powderedexplosive-detection training aid to escape from the packaging. Theanimal, such as a mammal, may then be conditioned to detect the vaporspermeating from the packaged powdered explosive-detection training aid.

Conditioning of the animal may be accomplished by e.g., rewarding theanimal, such as a mammal, with food or a toy when the animal displays aresponse at the location of the packaged powdered explosive-detectiontraining aid. For example, a mammal, such as a dog, may be walked to atraining area on a leash by a human trainer. The leash may then beremoved from the e.g., dog, and a command given to search. During thesearch, the trainers may avoid eye contact with the animal and maintaina neutral body position in order to minimize unintentional cueing. Upondisplaying a response at the packaging location, such as about one meterfrom the actual packaging location, an additional trainer outside of thetraining area and out of view of the e.g., dog, may toss a reward intothe training area the moment a correct response is exhibited. Upon anegative response, the e.g., dog, may be removed from the training areawith no reward. Such conditioning may be repeated.

Embodiments of the present disclosure are further described in thefollowing examples. The examples are merely illustrative and do not inany way limit the scope of the disclosure as described and claimed.

EXAMPLES Example 1. Packaging

A packaging according to the present application comprising a firstopposing flexible sheet prepared from 1059B or 1073 TYVEK® and a secondopposing flexible sheet prepared from PRECISION CLEAN™ HD film (6 inchesby 12 inches, 0.003 inches thick) was manufactured. The first and secondopposing flexible sheets were heat sealed around less than a peripherythereof, leaving an opening to a storage compartment that was formedbetween the opposing flexible sheets. The packaging was in the form of abag. The bag repelled water indicating its suitability for use withhydrophilic powdered explosive-detection training aids. The bag wasassessed to determine whether or not the powdered explosive-detectiontraining aids could permeate the bag as described below.

Example 2. Military TNT and Flake TNT

Materials and Methods

Military TNT and Flake TNT were used to test the permeability of thepackaging described in Example 1. Military TNT differs from conventionalindustrial explosives in that military TNT has significantly higherexplosive characteristics than those of conventional industrialexplosives. For example, military TNT is capable of splitting strongarmor due to its high explosive fragmentation. Flake TNT may refer togenuine TNT in a flaked form instead of, e.g., a powdered or cast solidformed TNT. Flake TNT may also refer to an inert simulant in a flakedform. The Flake TNT used in this example matches the density of realTNT, but is inert.

Military TNT pellets were obtained from a military TNT stick. Flake TNTwas obtained from the Transportation Security Laboratory (Egg HarborTownship, N.J.). The military TNT pellets (113.4 grams) and the FlakeTNT (50 grams) were each added to a separate bag, manufactured asdescribed in Example 1, and sealed with a heat sealer to close theopening to the storage compartment. In addition, 113.4 grams militaryTNT pellets and 50 grams Flake TNT, were each added to a separatebeaker. Each of the foregoing beakers and bags were placed intoindividual headspace glass vessels and stored overnight. Vapor samplesfrom the headspace glass vessels were collected into thermal desorptiontubes and analyzed on a Thermal Desorption Unit-Triple Quad-gaschromatography/mass spectrometry instrument.

Table 1 shows the amount of vapor detected from the permeable bags andbeakers (five replica of flake and military TNT). The average vaporconcentration of the military TNT, which was placed into a permeablebag, was 65 nanograms/liter (ng/L), while the average vaporconcentration of military TNT in a beaker was 97 ng/L, indicating thatthe present packaging was permeable to at least some military TNT.

The average vapor concentration of the flake TNT, which was placed intoa permeable bag, was 91 ng/L, while the average vapor concentration offlake TNT in a beaker was 81 ng/L, indicating that the present packagingis permeable to flake TNT. Further, the instant packaging was found tobe more permeable to flake TNT than military TNT (91 ng/L versus 65ng/L). This result occurred even though the amount of the military TNTpellets contained with the packaging was more than double that of theflake TNT (113.4 grams versus 50 grams).

Without being limited by theory, it is believed that the increase in TNTvapor from the Flake TNT in a permeable bag in comparison to that of themilitary TNT in a permeable bag may be due to the greater exposedsurface area of the Flake TNT. That is, the flake formation isrecognized as having a greater exposed surface area than that of themilitary TNT, which is cast in a solid pellet form. Moreover, the largeramount of Flake TNT vapor observed in the headspace from the Flake TNTin the permeable bag in comparison to that of the Flake TNT in thebeaker is likely because the surface area of the exposed Flake TNT inthe beaker is limited to the size of the beaker. In contrast, thesurface area of the exposed Flake TNT in the permeable bag is onlylimited by the size of the bag area exposed to the Flake TNT. Thus, evenlarger permeable bags should allow a greater portion of Flake TNTsurface area to be exposed, resulting in even greater vapor release.

TABLE 1 Permeability of Military and Flake TNT MILITARY TNT AND FLAKETNT TNT in permeable Concentration TNT in Concentration Flake TNT inConcentration Flake in Concentration Trial packaging ng/L beaker ng/Lpermeable bag ng/L beaker ng/L 1 4720 65.7 7530 104.8 6619.0 92.2 558277.7 2 4697 65.4 outlier outlier 5318 74.0 3 4320 60.2 6147 85.6 6646.092.5 6112 85.1 4 4599 64.0 5921 82.4 6460.0 89.9 6294 87.6 5 4926 68.68324 115.9 6482.0 90.3 outlier AVG 4652 64.8 6981 97.2 6551.8 91.2 582781.1 STDV 221 3 1144 16 94 1 454 6 Military TNT (1/4 lb. = 113.4 gramsFlake TNT (50 grams) Chamber Temp @25 ± 0.5° C.

Known standards, DNT and TNT (AccuStandard, Inc., New Haven, Conn.) wereinjected into a Liquid Injection Vapor Generator. The vapor samples werecollected into thermal desorption tubes and analyzed on a ThermalDesorption Unit-Triple Quad-gas chromatography/mass spectrometryinstrument. Calibration curves for DNT and TNT are shown in FIGS. 6 and7, respectively.

Table 2 presents the vapor concentration of the DNT standard (vaporpressure of 1.47×10⁴ Torr at 22° C.) and the TNT standard (vapor of5.8×10⁻⁶ Torr at 25° C.) in each of the military and Flake TNT samplesdescribed above. As indicated in Table 2, the headspace was filled withmore DNT vapor molecules than TNT vapor molecules. Accordingly, theresults indicate that the packaging according to the present disclosureappears to more permeable to compounds characterized by higher vaporpressures.

TABLE 2 Permeability of DNT and TNT Concentration Compound Peak A. %Ratio (ng/L) Military TNT DNT 6297654 98 3116 (Bare, 113.4 grams) TNT140077 2 Flake TNT DNT 8441396 98 4176 (50 grams) TNT 142855 2

Example 3. Permeability of Potassium Chlorate

226 grams Potassium chlorate (226 grams) were added to a packaging asdescribed above in Example 1. Potassium chlorate (226 grams) was alsoadded to a beaker. The packaging was sealed with a heat sealer to closethe opening to the storage compartment. The beaker and packaging wereplaced into two different headspace glass vessels and stored overnight.The headspace samples were collected into a glass-bead packed tube. Thetube was positioned in the sampling port of the headspace glass vesseland cooled to −150° C. in a cryogenic device. The samples were thenextracted in deionized water and solute was collected from each tube.The solution was analyzed on a Liquid Chromatography-Time-of-Flight MassSpectrometry instrument.

The mass spectrometry results revealed the presence of chlorine ions, anindicator of potassium chlorate, in the headspace sample. Accordingly,the packaging of the instant disclosure is also permeable to vaporcontaining potassium chlorate.

Example 4. Permeability of Triacetone Triperoxide

Non-detonable triacetone triperoxide (50 milligrams, 5% TATP and 95%diatomaceous earth) was placed into a tin container, which was thenplaced into a permeable bag. The bag was then sealed with a heat sealerand stored in a headspace glass vessel overnight. A second tin containercontaining triacetone triperoxide was also stored in a headspace glassvessel. Each headspace sample was collected into a thermal desorptiontube at room temperature. The thermal desorption tube was analyzed on aThermal desorption System-Gas Chromatography/Mass Spectrometryinstrument.

FIG. 8 shows that non-detonable triacetone triperoxide sample (in a tincontainer) entered the headspace. FIG. 9 also shows that non-detonabletriacetone triperoxide in a tin container and the present packagingentered into the headspace. Accordingly, the packaging of the presentdisclosure is also permeable to triacetone triperoxide.

Reference through the specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with an embodiment is included inat least one embodiment of the subject matter disclosed. Thus, theappearance of the phrases “in one embodiment” or “in an embodiment” invarious places throughout the specification is not necessarily referringto the same embodiment. Further, the particular features, structures orcharacteristics may be combined in any suitable manner in one or moreembodiments.

I claim:
 1. A method of training a mammal to detect a powderedexplosive-detection training aid, which method comprises: placing apackaged powdered explosive-detection training aid in a training area,wherein the packaged training aid comprises: first and second opposingflexible sheets with the powdered explosive-detection training aidtherebetween, the opposing flexible sheets being heat sealed along aperiphery thereof, wherein a melting point of the first opposingflexible sheet is substantially the same as a melting point of thesecond opposing flexible sheet, wherein at least a portion of the firstopposing flexible sheet is a semipermeable material, wherein thesemipermeable material is permeable to a vapor emitted from the powderedexplosive-detection training aid, wherein the semipermeable material isimpermeable to liquid water and particulate matter from the powderedexplosive-detection training aid, wherein the second opposing flexiblesheet is impermeable to the powdered explosive-detection training aidvapor; and conditioning the mammal to detect the vapors permeating fromthe packaged powdered explosive-detection training aid, thereby trainingthe mammal to detect the powdered explosive-detection training aid. 2.The method of claim 1, wherein the packaged powdered explosive-detectiontraining aid further comprises a sealing member having dimensionsgreater than the semipermeable portion of the first opposing flexiblesheet, wherein the sealing member is secured to the first opposingflexible sheet and covers the semipermeable portion of the firstopposing flexible sheet.
 3. The method of claim 2, wherein the sealingmember comprises a butyl rubber.
 4. The method of claim 3, wherein themethod further comprises opening the sealing member to allow thepowdered explosive-detection training aid vapors to permeate through thesemipermeable portion of the first opposing flexible sheet of thepackaged powdered explosive-detecting training aid prior to conditioningthe mammal.
 5. The method of claim 1, wherein the vapor permeableportion of the first opposing flexible sheet is a spun-bondedpolyethylene.
 6. The method of claim 2, wherein the sealing member issecured with a pressure sensitive adhesive comprising a rubber-basedadhesive.
 7. The method of claim 1, wherein the mammal is a domesticdog.